As issues in environment and energy are growing in the vehicle industry, many vehicle companies have been developing technologies to reduce weight of vehicle bodies for improved fuel efficiency.
Among materials used in a typical vehicle, metals may be comprised in about 65% of the vehicle weight and plastics may be comprised in about 13% of the vehicle weight. The portion of the plastic materials in the vehicle is increasing by replacing the metal materials used in the vehicle body with plastic materials in order to reduce the vehicle weight.
Particularly, polypropylene may be used in approximately 35% of the plastic materials in the vehicle. Polypropylene has advantages such as low material costs and excellent processibility. Accordingly, for simple injection molding, polypropylene may be used in vehicle interior parts such as automotive instrument panels, door trims, console bodies, pillars and trims, or coated and uncoated vehicle parts such as bumpers, side moldings and sill side moldings by adjusting content of the composition polypropylene to provide suitable flow characteristics such as flowability.
As described above, demands for plastic materials used as vehicle parts in the field of vehicle industry have been steadily increasing in continuous efforts to reducing weight and improving performance of the materials. Particularly, among various plastic materials, demands for polyolefin has been rapidly increasing compared to other plastic materials due to the effect in reducing weight from low density, simple recycling, relatively low costs and the like.
Required rigidity and impact characteristics are different depending on interior and exterior materials of the vehicle parts, and consequently, various resin compositions may be used in combination to satisfy the required characteristics.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.